Gas burner with flame retaining ports



March 1l, 1952 E E, TAVENER GAS BURNER WITH FLAME RETAINING PORTS 2SHEETS- SHEET l Filed Jan.. 31, 1947 March 1l, 1952 E. E. TAvENl-:R

E RETAINING PORTS GAS BURNER WITH FLAM" Filed Jan. 31, 1947 WW .W M

MM-WMMM Patented Mar. l1, 1952 GAS BURNER WITH FLAME RETAINING PORTErnest Edward Tavener, London, England, as,-

sgnor to Keith Blackman Limited, London, England, a corporation of GreatBritain Application January 31, 1947, Serial No. 725,442 In GreatBritain February 4, 1946l 1 Claim. l

This invention relates to improvements in gas burners. primarily thoughnot exclusively for use in baking ovens, normally in the form of a longtube, that is, long in relation to its Width, provided with alongitudinal slot or slots.

There has arisen a demand for a burner with a continuous, orsubstantially continuous iiame, but capable of much greater heat outputper unit of length than is practicable with burners of the usual types.

It is observed that when the mixture of gas and air issuing from aburner exceeds a certain velocity, it will not remain alight, the flame"lifting oi from the burner opening. If, however, another llame is heldadjacent to the issuing mixture, the latter will burn satisfactorily atvery` high velocities. This ignition llame, so termed to distinguish itfrom the. main or high velocity ame, can be fed from the mixture passingto the main flame, in which case the velocity of the mixture supplied tothe ignition flame must be considerably reduced before it reaches itscombustion point. Onesimple course is to use a restriction orifice inthe port leading from the mixture supply to the point of combustion.

For many years, use has been made of a low velocity ignition flamesurrounding a main high velocity flame. This ignition llame has usuallybeen fed through a number of small holes, each with a restricted supply,disposed around the main orifice. In other cases an annular ignitioniiame has been used.

For the present purpose there is required, in contrast, a substantiallycontinuous main flame, long in relation to its width.

A burner according to the invention presents a main slot (or slots) forthe main ilame, bordered along the length thereof, preferably on eachside, by a supplementary slot for an ignition llame.

For example, a main central slot may be provided by two strips,separated by a spacer. to give the required width of slot. On each sideof this assembly is placed a spacer so formed as to reduce thecombustible mixture to a low velocity at the point of combustion.Flanking these spacers are further strips, the whole assembly comprisingin this particular case seven elements, of which three are spacers.

The strip and spacer assembly may be iitted into a housing suitable forconveying combustible Vmixture and delivering it to the entrant side ofthe slots. This housing may conveniently be made from tubing,`slotted toreceive the strip assembly, and fitted with cross bolts to preventdistortion of the housing under the inuence of heat. The mixture may bedelivered to one end of the housing which may contain a furtherapertured tube for rationing the mixture longitudinally of the burner toprovide even or uneven heating, as required.

A gas burner according to the invention is illustrated in theaccompanying drawings in which Fig. 1 is a perspective view and Fig. 2 across section of the strip and spacer assembly constituting the burnerproper, and Figs. 3 and 4 are a longitudinal section and a crosssection, respectively, showing the burner iitted into a housing.

Referring to the drawings, the burner shown presents a central slot Illfor a main flame, bordered along the length thereof on each side by asupplementary slot I I for an ignition flame. The central slot. I0 isprovided by two strips I2, separated by a spacer I3, to give therequired width of opening. On each side of this assembly is placed aspacer I4 so formed as to reduce the combustible mixture for theignition flame to a low velocity at the point of combustion. Flankingthese spacers I4 are outer strips I5. The strip and spacer assemblyshown thus comprises seven elements, of which three are spacers.

The assembly is tted into a housing I6 suitable for conveying acombustible mixture, and delivering it to the entrant side of the slotsI0. II. The housing IG shown is made from tubing, slotted at Il toreceive the strip assembly, and tted with cross bolts I8 to preventdistortion of the tube under the influence of heat. The mixture entersone end of the tube at I9. 20 denotes a perforated rationing tube fittedWthin the housing IB and serving to ration the mixture longitudinally ofthe burner to provide even or uneven heating, as required. Heatdistribution along the length of the burner may be further regulated byadjustment of a conical valve 2| co-operating with an orifice 22 in apartition 23 fitted into the inlet end of the housing I 6.

The strips I2, I 5 may be held together by rivets, screws, welding orother means. 24 denotes straps for retaining the strip and spacerassembly in position in the housing I6. For convenience of manufacture,the spacers |31, I4 are preferably continuous, but serrated, theserrations being formed to permit the passage of mixture between thestrips forming the boundaries of the burner outlets I0, Il. In thevignition spacers I4 the openings are each shorter at the entrant sidethan at the discharge point, whereby the velocity of the issuing mixtureis reduced..

Again thin spacers may be used to provide the ignition name openings Il,the proportions being such as to cause considerable friction to theflow.

VAlso the length of passage from the entrant side to the combustion sidemay be selected to apply 5 the requiredireduction of'the velocity. Suchare rangements may be usedseparately,1 or.:irr combination.

An incidental advantage of the use of a narrovn-f ignition ame openingis that there is less like- 10` lihood of lighting back. in fact;lightingbackV is virtually impossible under normal operating conditionswith a very narrowopjening.-y

With the use of a very narrow ignitionilame.:l

opening il, a burner such as describedilcamzbe115,.

made very exible in performance, as,.vvithv a. high mixture pressure, aconsiderablelamountiof gas can be consumed per unit of length, the mainame being kept alight by the ignition name-orf: ames. can vbefmade.relativelyv low? before .the velocity of:` thevvmixtureftraversingthemain slot] 0 (orfslots) is.- reduced' sufficiently;i to.V cause.yriskof lighting; back.A

Thefinvention .is 2not limited to details. of. con-v struction. Thus,the relative.v heights of. the spacersv and .thestrips mayvary; e.. g.,the spacers may be-.sunk below the level of, theA strips, .as shown.

The .form of the serrations in the spacers. may very to. provide:continuous or interruptedflames.

Whilelhave described a burner. which. gives. one central main .flame andan ignition flame at. each side, the arrangement may be suchiasttoprovide.. one` .main Y flame and'v onev ignition. flame, or two mainnames. placed one on. each. side of. one4 ignition ame.

The relative widths .and/or thicknesses. of.' the strips and spacersmay.Y vary. For instance, for..

protectionpurposes we may`V bring the. outer. 4m

The outermost strips may be elinr'iated, their 45 place bein'gv takenby', the edgesorftheiburner.

housing.

Conversely, the rate of gas consumption 20 What is claimed is:

A gas burner including a longitudinally slotted tube, an assemblymounted in the slot in the tube and contacting the sides of the slot,said assembly comprising a plurality of plane parallel strip members-and:plane-sided serrated spacer. members-:..havingfoutwardly pointedserrations' interposed between and contacting neighbouring strip membersfor spacing Vsaid strip members apart,

thepointsof theserrations being ush with the outer edgesofmeighbouringstrip members, said strip and spacer members extending in parallelrelation .longitudinally-"of said tube with their planel sides` infcontact, these serrations extending belowtl'ie paralleli stripVmembers, said strip members-and. saidspacer members, collectivelyforming ..at.least one main slot and at least one supplementary slotconstituting passages for the owpffcombustion mixture to the outletVdefined by the upper edges of said strip and spacer members, thel.entr-ance'- to.. thea` main. slot being sub:-

stantially-f unobstructed byf a spacer.v memberi having widely f spacedi serrations. and interposed: between tWof striplmemb'ers, and .theentrance ato? 25"the supplementaryA slot being. considerably ob structedby a spacer.` member4 having. closely spaced serrations andiinterposedbetween. two

strip members:v

Ei'tNlihSTV EDWARD TAVENER-i..

REFERENCES CITED;

The*following'referencesarebof record in theM Number: Name? Y Datei.

73315235. Machlet:v July '1, 1903.. '791,923 Machlet; .Jr.'.. Junef',L1905;

1,105,031.; Hagemeyer .July.`28, 1914.; 1,519,056` Risinger Dee.y9,1,19241 2,396,800. Mills". .Mar.' 19,1,1946"=v 2,428,271 Ensignzetal.' Sept. 30,;.194'71` FOREIGN PATENTS f. Number Country,v4 Date259,868.. Germanyf. May 15,- 1913 501,143.

' Great-Britain f Feb.. 22, 1939..

